Baseball players who are named rookie of the year often endure what’s known as the sophomore slump. Why aren’t they quite as good the next year? “Somebody who gets rookie of the year almost invariably has had an unusually good season,” he says. “People have good years and bad years. After an unusually good season, it’s likely you’ll have a more nearly normal one the next time.”

Why do people spend more when they’re splitting the check?“It makes it seem essentially free to order a more expensive item,” says Frank.

Okay, here’s one that’s probably on everybody’s mind right now: Why do retailers kick off the holiday sales — and music — so early? “There are a lot of sales to be had of that stuff if you’re on the shelves before [other retailers]. So if everyone else puts them on sale November 1, and you go mid- October, you’re going to get the two-week window, where you’re the only one who has them,” he says. “Once you do that, it’s going to be compellingly in their interest to follow suit, and it … keeps slipping back.”